Is it possible that berries or rhubarb in the diet caused the brownish urine? Natural dyes in food can be passed as brown instead of yellow.
Blood turns brownish after it gets old, and old blood in the urine can turn the fluid brown. A urinary tract infection, or urologic surgery, can result in this leftover, old blood.
The following medical conditions can result in dark or brown urine in us two-legged mammals:
-Liver ailments, particularly cirrhosis and hepatitis
-Tyrosinemia, a rare genetic disorder: elevated blood levels of tyrosine, an amino acid
-Acute glomerulonephritis, which is a kidney malady that impedes a kidney's ability to remove excess waste and fluids
-Bleeding in the kidney, ureter or bladder
-Hemolytic anemia (abnormal breakdown of red blood cells)
-Serious muscle injury
-Melanoma (causes a dark brown or even blackish color)
-Copper poisoning